Tattoo tracks sodium and glucose via an iPhone

This modified iPhone case can be used to detect sodium glucose levels via a nanosensor "tattoo" (credit: Heather Clark and Matt Dubach)

Northeastern University researchers have developed a nanosensor “tattoo” with a modified iPhone that allows users to closely monitor sodium levels (to prevent dehydration), and glucose levels.

The team injected a solution containing nanoparticles into the skin. This left no visible mark, but the nanoparticles fluoresced when exposed to a target molecule, such as sodium or glucose. A modified iPhone (with three LEDs in a case) tracked changes in the level of fluorescence, indicating the amount of sodium or glucose present.

The tattoo contains 120-nanometer-wide polymer nanodroplets consisting of a fluorescent dye, specialized sensor molecules designed to bind to specific chemicals, and a charge-neutralizing molecule.

The researchers plan to create an iPhone app that will easily measure and record levels. Presently, the iPhone simply takes images of the fluorescence that the researchers then export to a computer for analysis.

The researchers also hope to measure dissolved gases, such as nitrogen and oxygen, in the blood as a way of checking respiration and lung function.